Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610064, P. R. China.
Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077, Hong Kong SAR.
Adv Mater. 2017 May;29(18). doi: 10.1002/adma.201606054. Epub 2017 Mar 3.
A wide bandgap small molecular acceptor, SFBRCN, containing a 3D spirobifluorene core flaked with a 2,1,3-benzothiadiazole (BT) and end-capped with highly electron-deficient (3-ethylhexyl-4-oxothiazolidine-2-yl)dimalononitrile (RCN) units, has been successfully synthesized as a small molecular acceptor (SMA) for nonfullerene polymer solar cells (PSCs). This SMA exhibits a relatively wide optical bandgap of 2.03 eV, which provides a complementary absorption to commonly used low bandgap donor polymers, such as PTB7-Th. The strong electron-deficient BT and RCN units afford SFBRCN with a low-lying LUMO (lowest unoccupied molecular orbital) level, while the 3D structured spirobifluorene core can effectively suppress the self-aggregation tendency of the SMA, thus yielding a polymer:SMA blend with reasonably small domain size. As the results of such molecular design, SFBRCN enables nonfullerene PSCs with a high efficiency of 10.26%, which is the highest performance reported to date for a large bandgap nonfullerene SMA.
一种具有较宽能隙的小分子受体 SFBRCN，其核心是 3D 螺二芴，被 2,1,3-苯并噻二唑（BT）所包裹，并以高电子缺的（3-乙基己基-4-氧代噻唑烷-2-基）二亚甲基丙二腈（RCN）单元封端。该小分子受体（SMA）成功地被合成，用于非富勒烯聚合物太阳能电池（PSC）。这种 SMA 的光学带隙较宽，为 2.03eV，与常用的低带隙给体聚合物（如 PTB7-Th）有很好的互补吸收。强电子缺的 BT 和 RCN 单元使 SFBRCN 的 LUMO（最低未占分子轨道）能级较低，而 3D 结构的螺二芴核心可以有效抑制 SMA 的自聚集倾向，从而使聚合物：SMA 混合物的畴尺寸合理较小。由于这种分子设计，SFBRCN 使非富勒烯 PSC 的效率达到 10.26%，这是目前报道的具有较大带隙的非富勒烯 SMA 的最高性能。
